The broad goal of this project is to help understand mechanisms for synaptic plasticity. One mechanism for long-term potentiation (LTP) or long-term depression (LTD) requires AMPA receptors recycling regulated by activation of protein phosphorylation downstream of the NMDA receptor. However, the specific cellular mechanisms that regulate AMPA receptors trafficking by synaptic activity remain largely unclear. To address this important problem, I have configured a biochemical strategy to characterize the machinery responsible for AMPA receptor trafficking by phosphorylation of stargazin, which is essential for functional AMPA receptors and is highly phosphorylated in brain. Due to the interdependence of the regulation of functional AMPA receptor by stargazin and the function of stargazin phosphorylation, this work has broad implications for mechanisms of learning and memory. [unreadable] [unreadable]